Of all the experiences we 21st century Americans crave, the biggest advertising idol we worship never was Tiger Woods — it's romantic intimacy. We long for a lively and loving, safe and sensual connection with a life partner. And when we aren't getting it, more and more Americans are finding cheap substitute experiences that provide more reliably immediate satisfaction.

These include such traditional sneaky thrills as affairs, prostitution and looking at pornography, but also new hybrids such as seductive texting, chat rooms and stripping by webcam. Wealthy, lonely and high-tech Americans can even have virtual sex with avatars if they want.

When do these behaviors constitute an addiction?

When sexual behavior works against intimacy in a love relationship, or against personal integrity for a single person who's not in love, it can be called "dysfunctional sexual behavior." It is an addiction when that behavior shows three or more of the following 10 signs:

■ Lack of impulse control.

■ Broken plans (frequency or duration of behavior exceeds what's planned).

■ Can't quit (persistent desire or unsuccessful efforts to stop for good).

■ Time or money loss to excess.

■ Preoccupation with thoughts of dysfunctional behavior.

■ Irresponsibility (behavior occurs during times committed to obligations).

■ Social fallout (negative consequences in work or family life).

■ Denial (little awareness when the behavior causes major problems).

■ Escalation (it takes more cost or risk to get the same emotional relief).

■ Withdrawal symptoms prior to and after the behavior.

How common is sex addiction? Our best estimates are that 6 percent of Americans have a sexual addiction. So, if your family has 20 folks over for Christmas dinner, odds are there's a sex addict in the house.

How do people become addicted? Without knowing it, most sex addicts have either trained themselves to become unable to resist the lure of lust, or been trained by someone else.

Addictions are fueled by trauma. When people are raped, victims of incest or sexually abused, they are usually attracted to repeat the traumatic situation, in a futile and subconscious effort to make it turn out differently, and too often to pursue sexual release they can't find any other way.

Addictions are fueled by shame. Though addicts believe shame will help prevent acting out sexually, it's actually a huge trigger. Recovery requires addicts to get forgiveness and break the shame cycle.

Addictions are fueled by other addictions. Sex addicts are usually addicted to something else: alcohol or other drugs (42 percent), eating disorders (38 percent), workaholism (28 percent), compulsive spending (26 percent) or compulsive gambling (5 percent).

Addictions are fueled by aversions. Many sex addicts have a binge-purge cycle that includes phases of sexual anorexia (extreme disgust and avoidance). Their significant others often go through this, too. All these aversions help trigger, maintain and rationalize the addiction.

Addictions are fueled by enablers. Some partners and loved ones believe they might have caused the addiction, or perhaps they could learn how to control or cure it. All three beliefs are false, and acting on them actually takes responsibility for addiction and recovery away from the addict.

Can a sex addict ever recover?

Since sexually addictive experiences produce massive amounts of dopamine in the brain, it's been said that sex addicts carry their drugs with them. So this is tough to treat. The good news is that research has identified 30 tasks addicts can do that extend the 12 steps to virtually assure recovery (see sexhelp.com). One study showed that more than 90 percent of those who complete even the first 19 of these tasks were still in recovery five years later without slipping back into addictive behaviors. Woods has started doing those tasks.

What are the prospects for getting well? Because most Americans have never personally known anyone who has successfully recovered from sex addiction, there is a huge stigma against addicts and their prospects for recovery. That's why treatment and recovery have to be as private and anonymous as AA used to be.

More than any other type of addict, the sex addict longs for loving intimacy with one other person for life, a longing that has often been regarded as a foretaste of heaven. The marriage of a sex addict ends up going double or nothing — it has to become twice as good and intimate as the average marriage, or it's very likely not going to make it.

How does a spouse expect genuine closeness not knowing whether marriage would be heaven or hell? The spouse of every sex addict faces that question.